Na-S Battery: Low-cost with four times the capacity of lithium | Hacker News Reader

Na-S Battery: Low-cost with four times the capacity of lithium

sydney.edu.au

The key word that's almost submerged in the article is molten.

Like previous sodium-sulphur batteries this one relies on a molten salt electrolyte, meaning you won't see it in your phone or laptop any time soon!

However, as it's being developed with the idea of grid-scale smoothing/backup, that's much less of a problem. (The square-cube law means that as you increase the volume of your molten salt cell, the surface area grows more slowly -- and thermal losses scale with surface area, so really big cells are cheaper to maintain at operating temperature.)

That also jumped out at me when I read it. However, later on they state that this reaction works at room temperature:

> Using a simple pyrolysis process and carbon-based electrodes to improve the reactivity of sulphur and the reversibility of reactions between sulphur and sodium, the researchers’ battery has shaken off its formerly sluggish reputation, exhibiting super-high capacity and ultra-long life at room temperature.

This is confusing. Can someone make some sense of this?

> exhibiting super-high capacity and ultra-long life at room temperature.

Maybe this is just bad writing? The battery (at operating temp) has high capacity, and (at room temp) can be stored for a long time? The wikipedia page indicates that it is normal to store charged molten salt batteries at room temp when not being used.

https://en.wikipedia.org/wiki/Molten-salt_battery

I think it might literally mean "operates at room temperature" as in 25-35 degrees C. Not really sure how it works but there seems to be a distinction between high, intermediate, and room temperature for the Na-S battery's operating conditions.

Quote from: https://www.tandfonline.com/doi/full/10.1080/21663831.2022.2...

    1.1. History of Na-S batteries

    Research on Na-S batteries originated in the 1960s, with the first research focused on High-Temperature Sodium-Sulfur (HT-Na/S) batteries, which operate around 300–350 °C. A molten Na anode (melting point=98 °C), a molten sulfur cathode (melting point = 118 °C) and ceramic β'-Al2O3 as solid electrolyte are assembled into the HT-Na/S batteries [11]. HT-Na/S batteries avoid the dendrite problem and have high electrical conductivity. However, it also has the defects of high working temperature, high risk, low energy density and high operation cost. And then, the Intermediate-Temperature Sodium-Sulfur (IMT-Na/S) batteries were innovated in the 1970s and operate between 120–300 °C. The IMT-Na/S batteries also eliminated the dendrite problem, but the electronic conductivity and the utilization of sulfur also decreased. Researchers have been intensively investigating Room-Temperature Sodium-Sulfur (RT-Na/S) batteries, which operate around 25 °C-35 °C. RT-Na/S batteries can completely convert S8 to Na2S, so they have a high theoretical energy density (1274 Wh kg−1)

Maybe they found a way to mix it into an eutectic mixture? The article doesnt say much on the specific chemistry of the liquid salt. https://en.m.wikipedia.org/wiki/Eutectic_system

The title of their article[1] is "Atomically Dispersed Dual-Site Cathode with a Record High Sulfur Mass Loading for High-Performance Room-Temperature Sodium–Sulfur Batteries".

[1] https://onlinelibrary.wiley.com/doi/10.1002/adma.202206828?u...

Just to add, yes, that paper is about solid state batteries.

I (incorrectly it seems) assumed that “molten” was just part of the manufacturing process. This take makes more sense.

Very important detail. Thanks for highlighting.

Not only does this limit practicality for phones, cars, but it limits practicality at all. Some of the larger utility scale solar-collector designs ended up failing because of the challenges of maintaining elements that involve molten salt.

The paper’s title is “Atomically Dispersed Dual-Site Cathode with a Record High Sulfur Mass Loading for High-Performance Room-Temperature Sodium–Sulfur Batteries” (https://onlinelibrary.wiley.com/doi/10.1002/adma.202206828?u...), so I guess you misread that.

No, these are room-temperature NaS batteries. They use some special electrolyte, but I have no idea how this really works. Their main drawback so far was longevity, but this battery has a capacity fade of 0.05% per cycle, which is on par at least with a poor Li-Ion battery. LiFePo4 is still superior in that regard, but the much higher capacity and hopefully lower cost (if they can be manufactured efficiently) might make up for that, hard to tell.

> but this battery has a capacity fade of 0.05% per cycle, which is on par at least with a poor Li-Ion battery.

20% lost at 400 cycles. This isn't so bad if it really offers 4x the capacity. In terms of usage it will last 1600 cycles comparatively speaking. Which is still far better than Li-Ion.

No, Li-Ion batteries can be twice as good:

"In 2003 it was reported the typical range of capacity loss in lithium-ion batteries after 500 charging and discharging cycles varied from 12.4% to 24.1%, giving an average capacity loss per cycle range of 0.025–0.048% per cycle."

(https://en.wikipedia.org/wiki/Capacity_loss)

And that was twenty years ago, things probably have improved. I think you have a wrong impression what is meant with "a battery lasts X cycles". That does not mean that it will be at zero capacity after 'X' cycles, but usually that it is down to ~70% of the initial capacity.

EDIT: Sorry, I missed the "comparatively speaking", so you mean when including the 4x capacity. You are right, of course.

I'd happily trade 2x capacity for 0.5x life in my cell phone battery, provided that the cell phone manufacturer just makes it easy to swap batteries.

Something that baffles me is how hard it's become to replace the battery. I had the original generation Galaxy S -- I loved that thing, because there was a little latch mechanism on the back-side. With a firm tug, the rear cover popped right off, allowing you to pop the battery out. It took less than 10 seconds to do a battery swap, which I used to great advantage while traveling (carried a second battery with me). Of course, back in those days, the typical battery capacity was not nearly as good.

In any event, I wish I could still do that with my current phone. It would be super slick if there was a tiny auxillary battery or 60-second hold-up capacitor too, so you wouldn't even have to shut the phone off.

>Something that baffles me is how hard it's become to replace the battery.

Why is this baffling? It makes perfect sense for batteries to be non-replaceable: you can make the phone slightly thinner, and you can charge owners a small fortune to replace them, which will usually result in them simply throwing the device away after a while and buying a new one. Just look at Apple: they pushed non-replaceable batteries (and also removed headphone jacks in favor of expensive airPods), and people love iPhones and can't wait to get the next version, even if it costs $1399 and they have to sell their kidney to buy it.

This is such a cynical take. By ditching removable bits they save on internal room which allows bigger batteries. I would take 25% better main battery life over removable any day. If you don’t mind carrying an extra item (because that’s what swappable batteries means — by the way how do you keep the spare charged?) then get an external. Even easier to swap and use, often supports pass-through charging, and doesn’t create yet another aperture that needs waterproofing.

I'm using a Fairphone 3. It's one of those repairable phones where you can replace faulty parts. The battery costs €30 bucks. For me it's not about carrying a spare battery, it's about throwing the old one away when it can't hold charge for a whole day, and installing a new one. So far I've done this twice with the FP3. I have no intention of replacing this phone any time soon. If I do, it'll be like the last time: I'll get another repairable phone (FP4? FP5?) Before that happens I might have to replace the lower assembly because the USB port is getting loose, but that's only €20.

You're missing the real reason for replaceable batteries: they need replacement after a few years because their capacity decreases with age.

Can they be recycled to get back close to 100% capacity?

My LifePo4 battery has a 6000 cycle guarantee at 60% capacity.

So its not even close yet

> So its not even close yet

Yes, if you compare just capacity fade, that's true. But the longevity of LiFePo4 comes with a lower charge density than Li-Ion, about 170 mAh/g. This NaS battery currently has 1017 mAh/g, so almost a factor of 6. If the capacity is higher, you don't have to cycle as often, but of course, mileage depends on the use case.

That lower capacity comes at a cost cut and a huge materials advantage. LFPs are made of highly available materials. (Lithium, iron and phosphate).

The higher capacity NMC batteries are constrained on nickel production.

The question is more how many kWh can you store and extract over a lifetime at a given cost rather than how many cycles can it take.

If the 5999th charge is only holding appropriately 60% of a LifePo4 battery you don’t get 6,000 cycles * full battery capacity.

True, but you probably will get more before the battery becomes unusable in total.

It would be very nice if batteries were super predictable as in 'perfect until the 6 thousandth cycle and then dead', instead you get this gradual drop-off to the point where a battery is no longer usable for its intended purpose. Whether or not that is at 60% of the original capacity or not is moot if it doesn't make it to the 60% in the first place (lots of batteries get murdered well before the end of their design life), on the other hand if that means that the drop-off itself slows down then you might be able to get much more life out of them when treated carefully.

The big ones - in my experience, which is obviously not the final word on this - is to ensure that you don't charge batteries when they're very cold, that you don't use currents in excess of what they're made for (and preferably a bit below that) and that you don't subject them to mechanical stress. If you live by those rules you can make them stretch for a very long time, enough for technology itself, rather than that battery, to make your battery obsolete.

Witness the old lead-acid batteries used in cars, telephone switch boards and submarines. In cars they would last a couple of years at best, in telephone switch boards and submarines they would routinely outlast the rest of the installation.

The faster battery life deterioration might even be desirable for those manufacturers with planned obsolescence in mind, especially phone manufacturers

A somewhat shorter lifespan might be a decent trade if the materials are much more recyclable and if mining is produces less pollution.

also if the batteries are cheap enough they can be considered "partially rechargeable" and swapped out when the capacity fades too much

I suppose partially worn out batteries can also find new uses, such as stationary power reserves, where they're not being cycled a lot.

Is it 0.05% of the remaining capacity, or of the initial capacity?

The paper, that red_trumpet posted down on the replies is about solid state NaS batteries.

The work describes a room temperature battery that uses an electrolyte of Na (sodium) in a propylene carbonate liquid carrier with electrodes made of graphene flakes with Mo and S embedded in the graphene framework. I don't know what the author of the article posted was trying to say when referring to molton Na-S, since it is not part of the battery described in the research, nor part of the manufacturing process. Probably the author did a search on Na-S for background, and not understanding how this differed, stuck it in.

Nope, the PR was poorly written (maybe the Department is experimenting with chatGPT ?).

Surprisingly the publication is freely available, and yes it's all room temp:

https://onlinelibrary.wiley.com/doi/10.1002/adma.202206828

My supervisor's wife was working at a pharma company back in the 2000s. Her job was to reproduce promising publications related to any conditions they were involved in. The reproducibility rate was something like 25%, which is higher than some other estimates I've seen looking across many fields, but still....

Incentives matter and right now they're the wrong ones

>Nope, the PR was poorly written (maybe the Department is experimenting with chatGPT ?).

ChatGPT probably would have done a much better job with access to the publication. Pretty soon, these lousy science journalists are all going to be out of a job when they can't even get basic facts correct, and the real scientists don't have time to write or review PR articles themselves, so an AI will fill that role instead.

That is not and never was the point -- sodium is in the same column as lithium on the periodic table, but it is significantly heavier than that, so mobile applications (cars, phones) are out of scope. Sodium is promising for stationary, community- or grid-level storage.

There are many good reasons to expect sodium batteries to beat li-ion batteries in specific energy. Yes, a sodium charge carrier is ~3.2 times heavier than a lithium ion, and yes, it holds a bit less charge, but none of this has to be relevant because in a normal li-ion battery less than 1% of the total mass is active charge carriers.

If you went by the simple properties of charge carriers alone, you'd expect lead-acid batteries to be at least 15 times worse than li-ion ones. However, the best lead-acid batteries are only ~8 times worse than the best li-ion batteries. Because even though the charge carriers are so much worse at doing their job, the chemistry is otherwise much more simple and easy to work with that it lets you pack a lot more charge carrier and lot less support infrastructure into the same battery.

Sodium is similar, in that if you have a viable electrolyte, you can expect to utilize a lot more than 1% of the mass of your battery for usable charge carriers. This is why it's absolutely possible for molten salt batteries to have specific energies much higher than the best lithium-ion ones. As far back as 2014 there was a lab-scale prototype that beat every li-ion battery then in existence. The big downside of course is the molten part -- these are stationary batteries not due to low specific energy, but the fact that they have to be heated above ~110C to operate, and it is much more economical to make such batteries as large as possible. And in that segment, the chase is not for the highest specific energy but the lowest cost per Wh.

you won't see it in your phone or laptop any time soon

I know it's (probably) a compound and doesn't have the same properties as the individual constituents, but still I wouldn't feel entirely comfortable carrying around sodium and sulphur in my pocket all day. Maybe I'll let other people prove its safety over a few years first.

Is there any particular reason? Seems pretty naive to make any assumptions about the properties based on its elemental composition. Lithium is incredibly reactive and toxic in its pure form but you surely carry that around. Do you ever consume table salt, a compound of reactive sodium and toxic chlorine?

The Wikipedia article mentions two types, molten and room temperature, each with their own pros and cons.

https://en.wikipedia.org/wiki/Sodium%E2%80%93sulfur_battery

The paper mentions making the battery at 300c (oven temperature) but the text talks about "room temperature" or "RT":

https://onlinelibrary.wiley.com/doi/10.1002/adma.202206828

"...thermally treated at 300 °C for 12 h. The Mo mass loading of S@MoS2-Mo1/SGF was ≈1.2 wt.%, measured by ICP-OES. The synthesis procedure of S@MoS2/SGF was the same as S@MoS2-Mo1/SGF but the thermal treatment was extended to 24 h. To prepare the S@SGF, pure SGF was used to replace Mo1/SGF. S@Mo1/SGF was prepared by pyrolyzing the mixture of Mo1/SGF and S at 155 °C for 12 h."

The only mentions of higher temperatures are for thermogravimetric analysis where they heat it to 800c and measure the amount of S as it varies with temperature.

Sorry, I can't resist the urge to repost this classic comment on a thread about new battery technology:

Dear battery technology claimant,

Thank you for your submission of proposed new revolutionary battery technology. Your new technology claims to be superior to existing lithium-ion technology and is just around the corner from taking over the world. Unfortunately your technology will likely fail, because:

[ ] it is impractical to manufacture at scale.

[ ] it will be too expensive for users.

[ ] it suffers from too few recharge cycles.

[ ] it is incapable of delivering current at sufficient levels.

[ ] it lacks thermal stability at low or high temperatures.

[ ] it lacks the energy density to make it sufficiently portable.

[ ] it has too short of a lifetime.

[ ] its charge rate is too slow.

[ ] its materials are too toxic.

[ ] it is too likely to catch fire or explode.

[ ] it is too minimal of a step forward for anybody to care.

[ ] this was already done 20 years ago and didn't work then.

[ ] by this time it ships li-ion advances will match it.

[ ] your claims are lies.

I have a very simple criterion: Do they have a production process designed for this new technology? That's the final step to commercialization and is often the barrier that prevents new chemistries from entering the market.

From a young age I've combed the shelves at public libraries and found handbooks on battery technology.

Often 1/3 of the book is devoted to ordinary batteries and the other 2/3 are devoted to "reserve batteries" which are able to deliver a high power density for a short time to power a missile or something like that. There was a huge amount of research on those and I think it's easier to make a battery work if it doesn't have to last very long.

NiMH batteries seemed to come out of nowhere. I remember Sony licensing the technology for "InfoLithium" batteries that eventually took over the world.

The market for batteries is bigger than it ever was. Grid scale batteries relax many constraints: molten salt batteries might be practical there. The South Africans thought this kind of battery might be relevant for cars in the late 1970's and 1980's

https://www.afrik21.africa/en/south-africa-the-zebra-salt-ba...

and it might be again with electric cars legitmized and if oil is out of reach.

>NiMH batteries seemed to come out of nowhere.

My initial thought when I saw your post was "weren't these just a relatively contemporaneous improvement on NiCad batteries?"

Checked Wikipedia and nope:

NiCad - Invented in 1899 and commercialized in 1910.

NiMH - Invented in 1967 and commercialized in 1989.

I had no idea there was such a long gap between the two.

I wonder if there was some kind of economic inflection point — it felt like that in my memory, too, where it felt like NiCad was advertised more as new thing in the 80s before getting replaced with NiMH. I wonder how much that perception was steered by what was common in the car battery space since that was probably the most known rechargeable battery for a long time.

In the RC car world, NiCad to NiMH was a big deal.

I think sodium ion will dominate the next 10 years of grid storage unless a sulfur battery like this can commercialize fast enough.

The sulfur chemistries might leave all the solid state stuff in the dust.

I thought of it as well, with the same result: this one looks like it could actually work for a change...?

True ... but we need new order or two of battery performance improvements, so the breakthrough must come from somewhere.

Nothing wrong with reposting it. As a matter of fact I think this should be posted every time there is a new battery announcement so we can all do the tick boxes.

[ ] it lacks thermal stability at low or high temperatures. [ ] it is too likely to catch fire or explode. [ ] it is impractical to manufacture at scale.

These are the only three I see as problematic or unknown. Which is not that bad.

I find it tiresome empty snark.

Better batteries are a really big deal. Is every promising technology gonna work out? Of course not. But there's valid reasons to be interested and excited. I like that these stories appear on HN so I can keep a rough understanding of how research is progressing. And usually there's some comments here from people who know the field a lot better. But to find those gems I have to scroll past a whole crowd of people posting this self congratulatory snark.

> I have to scroll past a whole crowd of people posting this self congratulatory snark.

Has this comment ever been posted more than once in a thread?

edit: and I honestly can't understand what is self-congratulatory about a list of issues created by somebody who is obviously interested in batteries, and has seen a lot of press releases with the same flaws. It gives laymen a sensible list to check the newest claim against.

It's not as bad in this thread, it's more that every single thread in this topic area has this sort of snark, if not the exact text template, as the number one or two comment.

Sure it's fair to say I should just ignore it. But I find it lowers the quality of discussion in a way I want to protest, so I'm doing so. It's a zero effort "dunk" posted reflexively.

If you'll let me ramble a little bit, part of why I push back on this sort of behavior is because of growing up around evangelical extremists. A huge part of their behavior is using and re-enforcing what I call "thought ending cliches." These are one size fits all rhetorical quips that function to shut down conversation. "Well it's all part of God's mysterious plan" being the most basic famous one. Climate change? "It goes in cycles." You get the idea.

This kind of empty reflexive contrarian snark does the exact same thing, so no, I don't see it in a positive light. It's not just a joke, it's a joke intended to shame people into stopping discussion.

Sodium-sulfur batteries are already in use for grid storage [0] [1]. They're large and they have to be kept hot, so they won't work for mobile applications. This article seems to be describing one that works at room temperature.

[0] https://www.energy-storage.news/uae-integrates-648mwh-of-sod...

[1] https://www.bestmag.co.uk/worlds-largest-sodium-sulphur-ess-...

These scientific advances in batteries are cool, but I don't take them as a specific indicator of what is coming. It is a numbers game, if there are 1000 scientific advances maybe 1 or 2 will survive the gauntlet and make it into manufacturing in the next 10 years.

It seems reasonable that there will be battery options that cost 50% as much and others that have 2x greater energy density in the near future. That seems great to me. Batteries will be viable and economical across most storage needs expect for aviation, shipping and seasonal grid storage.

Same. If you follow articles like this you’ll be constantly wondering what happened to “x”.

(“Graphene can do everything except get out of the lab”)

Specifically for grid storage I'd like to see more attention given to gravity batteries [0], the compressed liquid type.

Recently saw a video (in German, [1]) in which there was back-of-the-envelope calculation that a gravity battery built by hydraulically raising a cylindrical landmass with 1km diameter by 500 meters stores about 2TWh (recent yearly gross electricity consumption of Germany is 560TWh).

It's such a simple concept! Also, they are looking for investors: https://heindl-energy.com/

[0] https://en.wikipedia.org/wiki/Gravity_battery

[1] https://youtube.com/watch?v=pnomwGCBNAE

That is an obscenely large cylinder. And a large height to raise it!

Pumped-storage hydro (the cheapest and generally most practical gravity battery) is currently responsible for almost all grid-scale energy storage worldwide. I don't think it's fair to say it's not getting attention.

What's not getting attention is the use of solids for this. The main reasons are that you'd like to re-use most of the infrastructure of the hydroelectric dam you wanted anyway, and that liquids make for simpler engineering in these cases.

What is interesting about a quick look at the Heindl Energy solution is that it looks like basically pumped hydro.

The difference is that the water is sitting in a large cylindrical space underground with a large (minimum 100m / 300ft diameter) rock piston sitting on top of the water.

Eliminates the need for mountainous terrain with a high lake-like geometry to pump the water up out of the gravity well — they can build this in the flatlands

I just had a wonderful and possibly stupid idea. How about pumped hydro with a huge storage tank on the surface and then another huge one at the bottom of a cavern made by an underground nuke test? The main problem of course is that the underground cavern is in the middle of nowhere and radioactive. Maybe you could remediate the pollution in the cavern by filtering the actinides while pumping the water around?

There are simpler technologies that already exist on this principle pumped hydro being the main one this proposal seems like overkill to have so much storage in a single location

Well of course you can divide up the mass and build several smaller installations.

I was merely hinting at the fact that pumped hydro storage can be made more compact and flexible by compressing the liquid with a piston.

I'm assuming it's a cylinder 500 m tall, lifted by 500 m so it almost clears the hole (assuming basalt at 2.9 g/cm^3, that's only 1.6 TWh, but close enough.) Watching a 1 km-wide 150-story structure rise from a hole and then disappear would certainly be a majestic sight. However, a few issues:

- The Mir mine, 4th deepest open-pit mine in the world, has roughly these dimensions (1,200 m wide x 525 m deep) [1]. Of course, its approximately a cone, so its total volume would be about half the proposed cylinder. The mine took 40 years to excavate, albiet in very harsh conditions.

- Simply removing the rock from the hole, with 100% efficiency, would expend 1 TWh of energy (average lift 1/2 of total height). If diesel powered construction equipment is used, theoretical maximum efficiency of just the engines is 50%, realistic is more like 20%. I'd be surprised if you could get a total efficiency of over 1 or 2%.

- Of course, you'd also spend energy moving the overburden away from the hole. If the angle of repose was 1-in-5, then the pile would be roughly 150 m (45 stories) at the tallest point, and form a circle 4 km wide centered around the hole.

- You could be clever, and just dig out the circumference and bottom of the cylinder. At the bottom every square meter would have 500 meters of rock sitting on top of it. That's 1.5 million kg, or 14,000 kPa (2,000 PSI). That doesn't sound... impossible... but it would require a dense forest of supports. It would be the world's most expensive room-and-pillar mine [2], by several orders of magnitude. Integrity of the rock would be a problem, too. A fault wouldn't just risk a tunnel wall blow-out or cave in, it could litteraly drop a 500 meter mountain on your head.

- Speaking of pressure... how do you perfectly maintain the integrity of a 3 km circumference piston ring? The water is going to really, really want to slip past the rock piston. Anywhere it does it will have very serious erosion. How do you fix a problem? Picture one of those submarine movies with water spraying everywhere, but unable to shut it off.

- Speaking of pressure, again... how do you maintain the integrity of the rock? You'd have to girdle it in a 3 km x 500 m tall wall.

- You still need a very large water reservoir.

[1] https://en.wikipedia.org/wiki/Mir_mine

[2] https://en.wikipedia.org/wiki/Room_and_pillar_mining

Good clarification. Perhaps it would be better then to build these at smaller scales (as they suggest on their website) ;)

In the video this example is chosen to compare it with the area requirements of conventional pumped hydro as well as to show what magnitude of energy storage would be necessary to compensate for fluctuating solar/wind production.

I wonder how does it stack up against non-flow zinc-bromide batteries, which apparently are already being produced and are aiming for the stationary storage market:

https://www.pv-magazine-australia.com/2022/09/30/gelion-unve...

The 2MWh/yr plant is very small, but reportedly it's a repurposed lead-acid facility because the production process is similar enough.

Seems to be a legitimate advance in a long-disregarded battery tech, I’d be very happy if this ends up reducing lithium mining.

Indeed, and it might also drive down prices. Sodium and sulphur are much more abundant than Lithium (1150x and 260x respectively).

https://en.wikipedia.org/wiki/Abundance_of_elements_in_Earth...

Does the 1150 take into account all the oceans full of NaCl? It sounds a little low.

Sodium and sulphur are very cheap and easy to get, but not because of this.

Sulphur is a byproduct of lots of different industrial processes, usually oil refining.

Sodium is most commonly extracted from seawater.

Frequency of elements in Earth's crust is a pretty poor approximation for how easy they are to mine.

This wiki page has a surprising graph https://en.wikipedia.org/wiki/Abundance_of_elements_in_Earth...

The "rare earths" are actually just as common as Si. It just shows we won't be running out of them anytime soon, it's just a matter of finding ways to extract them.

Although, by looking at the places where they are more abundant, I wouldn't be too optimist, at least with the current geopolitical climate.

https://www.statista.com/statistics/277268/rare-earth-reserv...

Si is the symbol for silicon, which is the second most abundant element in the Earth's crust (after oxygen.) The REEs are certainly not as abundant as that. Si is 270,000 ppm; cerium is 60 ppm.

You're right, I'm dumb, the graph is 0 at 10^6 Si. So rare earths are 1 million times more rare than Si. It's similar to copper and Nickel though

Not a million times more rare, more like ~10,000 times. Also, Ni is more abundant in the oceanic crust than the continental crust. Lots of Ni in mantle rocks (peridotite is about 0.1% Ni.)

It's interesting comparing the abundance of copper (and even more so, tin) and iron. It was a huge transition in resource availability when the iron age began.

I’m not sure how you’re interpreting that graph, because Si (Silicon) and Na are orders of magnitude more common than the rare earths. You might have missed that it’s a logarithmic scale.

Is the material that ends up in the cell a significant part of the cost? If steel was free, ICE cars could be dozens of dollars cheaper than they are. I guess material costs are a much bigger factor in batteries, but in many other products is so low that "much bigger" could still be tiny.

Yes. The electrification movement isn’t any “green” if you take into account the impact of current battery technology.

PS: the impact of battery technology - I’m not only talking about mining but the entire cycle: usable life, reverse logistics, disposal and recycling, dealing w/ water and soil contamination.

Ah yes.

Digging for coal or gas or oil, fracking, etc: just fine

Mining for (significant less amount of) lithium or other metals: "oh look they're ruining the environment"

As most discussions go, they're heavily biased towards the status quo

Both of those can be bad at once you know...

A lithium mine is much more devastating to the environment than an oil well or franking. That doesn't mean either of these are really good options despite what either side wants to pretend.

This sort of both-sidesing doesn’t further the conversation at all. Do you really think the person you’re replying to doesn’t know that mining Lithium isn’t without its environmental costs?

The person you’re replying to quite correctly notes that mining Lithium is an improvement over extracting coal, oil, and gas. The term “green” is so nebulous snd ill-defined that it’s not worth talking about.

The best thing humanity can do for the earth is clearly to remove ourselves from it. Anything less than that is compromise. Sure. But sitting here saying “there’s no such thing as ethical consumption” doesn’t really get us anywhere.

Precisely; it’s not big oil propaganda to understand the environmental effects of lithium mining, just as it’s not lithium propaganda to acknowledge the equivalent consequences of the oil industry on the environment.

But if we get to have a way to move at super-human speeds (ie > 5 km/h walking and > 30 km/h running), cheaply and without environmentally detrimental consequences, that’d be great :)

(Fellow cyclists, I know, cycling is an excellent solution for single-person small- and mid-range movement. I’m thinking here of mass transportation and goods transportation, where it’d be hard to use cycle-powered lorries across continents.)

What makes a lithium mine so bad? Oil wells prone to generate lots of saltwater, too.

No doubt that mining lithium has negative impacts, but those negative impacts feel localized in a way that can in principle be mitigated and cleaned up, and though bad for local communities, it doesn’t pose existential risk. This is in stark contrast to the fossil fuel cycle which distributes pollution globally into the atmosphere, and will be tremendously difficult to undo.

Untouched National Parks don't bounce back to pre mine status so that's a Yes to "in principle" but a No to "in practice".

Lithium exploration drilling near Litchfield National Park raises sustainability questions [1]

> University of Queensland professor of conservation science James Watson says that mining associated with renewable energy could cover about 50 million square kilometres of the Earth's surface by 2050.

> His prediction is startling.

> "About 10 per cent will be in national parks and protected areas, another 7 or so per cent will be in areas that have been identified as critical biodiversity areas to sustain species and stop extinction, and a further 15 per cent or so will be in our last remaining wilderness on the planet," he said.

I've spent a few decades in mineral exploration, in geophysics and in mapping global mineral and energy resources.

We have some real issues to sort out going forward with respect to resource extraction and the rights of indigenous people and wilderness.

[1] https://www.abc.net.au/news/2022-12-13/lithium-found-near-li...

What percentage of national parks will be affected by climate change? I see your point but if we have two bad options and one is absolutely worse than the other, making them look equivalent because they have some environmental impact is not helpful to protecting as much if the environment as possible.

A surprisingly high percentage in National Parks globally (ie. many different jurisdictions) that are also (or adjacent to) indigenous lands with various treaties and contracts.

eg: The US has one ~$64 billion copper resource (leased to Anglo - Australians) in native lands [1] which is an as yet unresolved and sizeable can of worms, and that's barely the start of the list (although it is the largest global pending copper project).

There's a nice GIS directory of such things that we (here in W.Australia) compiled a decade ago (along with automation to run it forward) that's now a bit paywalled [2]

[1] https://en.wikipedia.org/wiki/Resolution_Copper

[2] https://www.spglobal.com/marketintelligence/en/campaigns/met...

Both can be bad, and both are bad.

But it looks like a lot of people assume they are just as bad without any quantitate or qualitative assessment.

Lithium mining is way less bad than oil extraction in both dimensions. If that lithium can offset oil consumption it looks particular good.

>A lithium mine is much more devastating to the environment than an oil well or franking.

This isn't true at all. Lithium is mined in much smaller quantities and in fewer places. In some cases (Cornwall, e.g.), it can be obtained as a byproduct of geothermal energy. It can also be recycled. By contrast, the Wikipedia list of environmental disasters has an entire section devoted to oil:

https://en.wikipedia.org/wiki/List_of_environmental_disaster...

You have not only the impact of mining but also the problem of reverse logistics for correct disposal and recycling of those toxic batteries that don’t even last long. Batteries contaminate soil and water in a way that’s much harder to control if it start piling up everywhere. And today’s world can’t even solve the disposal of plastic.

With intelligent charging practices (which often come at the expense of stored energy) and temperature control, modern lithium cells asymptote to ~20% capacity loss and stay there for, well at least since the model S came out, still counting. Or that was the case a couple years ago when I looked into it. The difference in the battery life in a leaf vs a tesla is qualitative not quantitative. The motivation to make phone batteries last longer wasn't there at first until it provided negative press, now intelligent charging is fairly common in phones. Thermal management is harder.

Lithium batteries are a great source of lithium, and bigger of them, like laptop batteries, largely get recycled even now, AFAICT. Lithium + iron chemistries in particular avoid seriously toxic components.

Both lithium and plastics are far less nasty than, say, ash from a coal-burning plant, with its sulfur, mercury, and radioactive stuff. Retiring these is a higher priority thing, IMO, than improving lithium mining cleanliness (though an improvement is always welcome).

Brine extraction of lithium leaves some waste but largely uses solar power to operate and isn’t particularly invasive. Mining Spodumene is as bad as any other mining, and open pit mining is common. There’s some other techniques that use large amounts of highly concentrated acid. But it’s a really hard case to make that the oil economy is somehow a better environmental story for sure.

So its not fossil fuel funded climate change denial, it's actually about the ethics of lithium mining?

Lithium on earth is in salt form. Most coming from dry salt beds in South America. Big US project is to extract it from the Salton sea. Fracking is much worse and contaminates water tables not to mention all the methane releases that cause global warming.

you're out of date, half of current lithium production is hard rock mining of spodumene in australia

Imagine a desalination process funded in part by producing battery-grade sodium.

All you practical people who wait until there is real world manufacturing promise are missing out on the pleasure of wild imagination.

Imagination is great, but there's a blurry line between "imagine a thing and make it happen" and "tell happy stories instead of working".

One belongs in science journals; the other belongs in Astounding Stories. Both have their place, and there's even some overlap, but it's no surprise that grumpiness occurs when the conversation crosses that blurry line too far (in either direction).

"we're all doomed"

"wait, there's a new battery tech that could solve some of the long-standing problems with moving to a clean-energy abundant civilisation, and yesterday they achieved fusion ignition for the first time"

"bah, these are all rubbish and will never make any difference, we're still all doomed"

Would love to hear from domain experts here. Reading the article one finds that they only created very small cathodes rather than anything close to a 'consumer sized' battery.

(The full text of the paper is available for free at https://onlinelibrary.wiley.com/doi/10.1002/adma.202206828)

It's just more science by press release. Wake me up when there's a real manufacturing process developed.

I'm not a battery expert, but I have looked into Na-S before. While it's a great rhetorical bludgeon in arguments about what batteries can do in theory — we'll never run out of sodium or sulfur — actual costs of Na-S installations are consistently much higher than lithium or other battery types. For example, this review cites a present system cost of over $400/kWh:

https://www.mdpi.com/1996-1073/13/13/3307

A new scientific development can be cool, but it won't directly reduce costs, since it's not actually an industrial process. A lower operating temperature might simplify construction. But all that remains to be seen.

EDIT: if you read the original paper in TFA you will find that molybdenum, an extremely rare metal, is key to the cathode, though only at 1.2% by weight. Interpretation unclear.

> Reading the article one finds that they only created very small cathodes rather than anything close to a 'consumer sized' battery

There are few articles on 'consumer sized' 18650 sodium-ion (Na-S, Na-ion) battery (aka NIB):

October 2019: Developing O3 type layered oxide cathode and its application in 18650 commercial type Na-ion batteries[0]

May 2022: First 18650-format Na-ion cells aging investigation: A degradation mechanism study[1]

August 2022: Remaining useful life prediction for 18650 sodium-ion batteries based on incremental capacity analysis[2]

[0] https://www.researchgate.net/publication/336562138_Developin...

[1] https://www.researchgate.net/publication/359078973_First_186...

[2] https://www.researchgate.net/publication/362754837_Remaining...

Let me know when I can buy 30kwh worth of energy storage so I can compare it to Lifepo4 costs [1]

[1] $10,500 https://signaturesolar.com/eg4-ll-lithium-batteries-kit-48v-...

LiFePO4 batteries are really magical; mostly made of easy-to-find materials, good density, long lifetime, hard to make explode.

LiFeYPO4 Have a wide temperature range of -45° to 85° C. Uses Yttriumbut cost more

Those are the more expensive packs with LCDs. The cheaper, simpler packs are only $9000 and just as good.

I’m a layman as concerns batteries, but I’m old enough, just like photovoltaics, for the prevailing view to be: this is at the asymptote, it’s not getting any better.

I’m glad some people decided not to listen to that bollocks.

For solar panels I agree, there's a hard limit of how much energy per area the sun itself gives, and how much efficiency you can physically get out of that.

For batteries: biological creatures store more energy more densily, yet safely, so there's still headroom.

I think the general thinking is that cost is going to be the determining factor for PV. It it gets to be cheaper than paper, for ex, you could just put it everywhere.

But there are still lots of wins - we’re only in the low 20s for efficiency and mostly catching visible light. There’s also environmental, long life, etc ways to improve as well.

Solar is by far the cheapest form of energy by a significant margin. It is already at the point where it makes sense to put it everywhere, and have concentrated large scale generation.

For solar to win, we need to solve energy storage, or perhaps the energy distribution problem. There is no amount of solar which will give you power 24 hours in a day in a single location.

Energy storage is the best short term solution. If we can capture peak solar generation and move that energy to the peak demand period, we can have a serious discussion about moving away from coal for baseload generation. It won’t be needed during the day, and the demand periods covered by storage.

However, for solar to really win, we need to think bigger with our energy distribution networks. Think of a global scale distribution network, like an internet for electricity.

If you can send an IP packet from your computer across the world, why not energy?

With a sufficiently large interconnected global scale network of renewable generators, energy storage becomes less important. We don’t need gas pipelines, we need longitudinal and latitudinal HV distribution networks.

> For solar to win, [...] If we can capture peak solar generation and move that energy to the peak demand period, we can have a serious discussion about moving away from coal for baseload generation.

Why is it always solar vs coal? The generation mix depends on your network, but AFAIK, the world is already moving away from coal towards natural gas; and solar is often complemented by wind.

> If you can send an IP packet from your computer across the world, why not energy?

This has already begun in the form of the new transmission line under the North Sea between England and Norway, which will be used to store wind power from the UK in pumped hydro facilities in Norway. [1]

But sending electricity at grid transmission levels across major ocean distances may not pencil out economically.

Politics also comes into play. In the US for example, the Texas grid won't even attach to the rest of the national grid.

1. https://en.m.wikipedia.org/wiki/North_Sea_Link

But afaik, solar panels currently convert only 20% of the energy to electricity, can you explain why this is close to the theoretically or practically possible maximum?

I’m the wrong kind of an engineer to have a cogent thought / argument about that.

My remark was more of an anecdote that these things are getting better in spite of a great deal of pessimism about them over my lifetime.

There's a theoretical limit of 55% for unconcentrated, 85% for concentrated sunlight. I'm not sure about the exact thermodynamical reasons for those numbers.

But claims of "1000x better" can physically never be true, unlike for batteries (e.g. antimatter, no matter how impractical, has millions times more energy density)

It depends on how you operationalize the claim and when you start the timer.

In 1975, the cost per watt for solar PV modules was $105.70 per watt, when normalized for inflation. In 2020, that number was $0.20 per watt. (Source: https://www.iea.org/data-and-statistics/charts/evolution-of-... )

That a 528x improvement. If the price goes down in half again, quite possible with economies of scale, you have 1000x better in a significant measurement that counts.

> For batteries: biological creatures store more energy more densily, yet safely, so there's still headroom.

Conversion losses are bigger tho

I'm not looking forward to cleaning my house battery's litter box.

Solar panels still have some dimensions along which they could improve, for example:

* efficiency in low-light situations

* efficiency when parts of the panel are covered

* cost

I guess the inverters could also be improved...

They don’t mention the actual specific energy of the completed cells in Wh/kg. Also, “four times of WHAT?” They need to compare like-to-like, which would mean comparing to an equivalent Li-S cells.

Li-S cells usually have much higher specific energy than regular lithium ion. I doubt these cells are better, considering sodium is heavier than lithium.

The highest lithium ion cells you can get now are Amperium cells at 390Wh/kg, plus the metal anode Licerion cells at over 400Wh/kg. That’s not counting lithium sulfur which can get to 650Wh/kg (but are still stuck in the lab).

They say the charge capacity is 1017 mAh/g. That is about four times the value of a typical (good!) Li-Ion battery.

Isn't that quite close to the magic number which makes electric planes a viable option? 1 kW = 1 kg; Musk said something about that in a podcast I think...

That's specific power, not specific energy. Do you mean 1 kW*r/kg?

Yes of course, I meant to say 1 kW·h = 1 kg; but I'm not certain if I remember correctly now; I could be off by a factor of 10 I guess. It was either 1 kg battery weight = 1 kW·h, or perhaps he said 10 kW·h had to be contained in a 1 kg battery to allow all types of air travel.

I think the 100 kW·h Tesla batteries found in the Model S/X weigh around 750 kg; so I guess electric air travel is still difficult unless a battery breakthrough happens; at least in terms of weight.

... assuming the cell voltage is the same ?

A quick google suggests Na-S cells at high temperatures are ~2.1V nominal (as opposed to 3.2V for LFP), but I lack the physics chops to parse the paper in the article to validate this. Anyway this sounds like a tiny experimental cell and for real world applications you'd want to see the Wh/kg for a fully packaged product.

> for real world applications you'd want to see the Wh/kg for a fully packaged product

Oh, absolutely, there's still a lot of stuff that could prohibit this technology from ever becoming an actual product. AFAICS, they also don't say anything about dependence an ambient temperature, for instance. It might be that this thing disintegrates as soon as it's freezing. Or, actually the most likely: that it's simply not possible to build this thing at scale with reasonable cost.

Not useful without the cell voltage. Need both to figure out the energy storage. Anyone?

Cell degradation was tested at 1V - so conveniently right around 1,000wh/kg.

Is that for a complete cell or just an electrode? If it's not specified, you can bet it's just for the electrode. Complete cell is what matters (or to be strictly true, a full battery... but that's another story).

Plus the voltage difference... IIRC, Na-S is 2.1V compared to 3.7V nominal for Lithium-ion, high voltage versions sometimes up to 4.35V max voltage. Perhaps a factor of 2 difference in voltage, plus it's only counting a portion of the cell mass.

They tested the drawdown at 1V with cells over 1,000 mah/gram so >1,000wh/kg if that voltage is their operating voltage.

This would be great also if, during damage situations they are less harmful than Lithium Ion batteries (which cause very hot, self sustaining fires for hours and hours!)

I would think any dry cell would have this as a problem? If you stuff a kWh into a box and get it back out without adding anything, there is a kWh in that box, and I think all these sorts of reactions proceed faster at higher temperatures, so wouldn't runaway always be a possibility?

This is all FUD, and I wish people would stop repeating it. Battery fires in vehicles (which I assume is what you're talking about) are objectively safer than gasoline fires. They just are.

It's true though that they have to be fought differently, because they can't be extinguished by flushing the fuel away as you can for liquid fires. So the "hours and hours" bit is sorta true, I guess. But having to keep people away from a battery fire for a while while you hose it down is an annoyance, not a safety concern.

In any case the battery under discussion is a molten electrolyte thing intended for grid storage, not vehicles.

> This is all FUD, and I wish people would stop repeating it. Battery fires in vehicles (which I assume is what you're talking about) are objectively safer than gasoline fires. They just are.

They just happen way more often, petrol tank is smaller tucked in usually somewhere in the back of the car, VS battery cell where just puncture can start a fire where gasoline can "just" leak without catching fire. Althought I imagine chance for that grows a lot with old cars, once they start to rot from corrosion

> They just happen way more often

I don't think that's true either? Obviously the FUD angle means that it Makes Big News when EVs burn. But gasoline cars burn all the time.

Look, if there's evidence for battery safety issues then let's discuss it. But there isn't. There are millions of EVs on the roads now. Can we even name one accident where someone was injured by an EV fire? It's just not there. This is wrong. What you're repeating is wrong.

> petrol tank is smaller tucked in usually somewhere in the back of the car

I think most car fires are not from the fuel tank leaking, but instead from a short somewhere in its electric system, or from a leaking hose spraying flammable liquid (fuel, oil, etc) onto a hot surface (like the motor). Compared with an ICE vehicle, an EV should have less hoses with flammable fluids, but more parts on its electric system.

With batteries is that there are way more factors than just capacity. You need thermal run way, cold/hot weather perf, heat generated, charge time, numb cycles before capacity is 80%, weight power ratio, scalability and cost

Some applications are easier than others. Grid storage, for example, can be in climate controlled warehouses, do optimal charging cycles to maximize longevity, don’t care about weight, etc.

Li-S is already 2.5x the energy density of TNT.

Before you say "petrol", petrol is typically not carried in the form petrol/oxygen fizz and its energy density is therefore zero.

likely because the logistics of handling and utilising an energy source that can materialise the entirety of its stored energy instantly has some safety concerns.

requiring air is not a limitation, it’s a feature.

I'm saying I'd rather not be near a 100kW-h Na-S battery. Current Li-Po batteries require quite some shielding at tiny a fraction of the energy density if you don't want to burn.

TNT has actually pretty low energy density - lower than chocolate chip cookies if I remember correctly. It's only used because of its ability to deliver it all in one go - something cookies lack. Energy density alone is a fairly inadequate metric to decide how dangerous some material is, and what precautions to take handling and transporting it.

Just as petrol, cookies have energy density of zero until mixed with oxygen. Just like TNT, or more like black powder, batteries have all components required to yield energy in one enclosure, which is why there are battery explosion videos and no cookie explosion videos.

I was never good with chemistry, the battery sounded icky to make. I'd bet on the Iron Edison battery or the iron rust battery instead.

How do you process them once they run out of reasonably efficient cycles?

Reconditioning facilities? wastes? etc?

Considering the main ingredients are sodium and sulfur, recycling should not be a major problem. Those are commonly used elements and not particularly toxic.

This question is always asked about EV batteries. Their recycling is something that is being developed but is still in prototype phase. Actual production scale recycling is not feasible yet because the number of retired EV batteries is too small to be efficiently recycled. That will eventually change but since EV batteries are generally lasting for a decade or more, it will take several years before we start seeing significant numbers needing to be recycled. I would expect that the same story would apply to these batteries if they are deployed.

"recycling should not be a major problem", well, this is where more details would be more than welcome.

Since they are still developing this as tech, I am not surprised if they are not really discussing how to recycle it.

Recycling would depend on how much of this ends up getting built, how much value there is in the components, and whether there is a cost/risk of not recycling. If only a small number are ever built, then recycling isn't much of a concern.

There doesn't seem to be anything in here that is radically different than other batteries and the components are less toxic than many.

4 x the energy density, but 8 x the mass. These will be heavy batteries. Kinda defeats the point.

Good for plenty of applications, such as power plants and renewables.

While I welcome this advancement it still seems like a solution to the wrong solution for another problem.

Very unclear what you mean. Large-scale, cheap, safe, and environmental energy storage is a huge issue that is nowhere near solved yet, so more solutions are absolutely a good thing.

Time will tell. All new battery technologies solve one problem but create two more.

Edit: I'm not necessarily talking about technology problems. There are geopolitical and environmental problems too :)

https://www.energy-storage.news/basf-takes-sodium-sulfur-bat...

capacity is but one of many characteristics of a successfully battery technology. it's important to consider just about every possible factor,

capacity, power density, charge and discharge rate, lifespan / shelf life, safety, voltage range, temperature ranges while charging, discharging, cycle count.

And, also, the performance of these attributes under various temperature profiles.

This list is far from exhaustive, I'm not a battery expert but just something I came up with in a few minutes of thought. So, gtfo with your capacity claim. Every few months a battery break-through article comes out. I've become de-sensitize to this type of news.

What is your comment actually adding?

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